Packing structure for subsurface well apparatus



Aug. 8, 1967 G. R. JOHNSON 3,334,907

PACKING STRUCTURE FOR SUBSURFACE WELL APPARATUS Filed Aug. 24, 1964 I 3heets-Sheet 1 III . INVENTOR. Gqo/PY R. (.IbA/A/SOA/ BY mmkzw A rraeA/EY5.

8, 1967 e. R. JOHNSON 3,334,907

PACKING STRUCTURE FOR SUBSURFACE WELL APPARATUS Filed Aug. 24, 1964 5Sheets -Sheet 2 "If. I /4a 1 4;, I I, V v v I N VE N TOR. 642 Y R 0(17/01/50 MIC /ES Aug; 8, I967 5 R. JOHNSON 3,334,907

PACKING STRUCTURE FOR SUBSURFACE WELL APPARATUS Filed Aug. 24, 1964 A 3he ts-Sheet 5 pee-awe! are; ELEMENT! 9255mm; 0w

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INVENTOR. Gmyk. JAM/$0M United States Patent 3,334,907 PACKING STRUCTUREFOR SUBSURFACE WELL APPARATUS Gary R. Johnson, Anaheim, Calif., assignorto Baker Oil Tools, Inc., City of Commerce, Calif., a corporation ofCalifornia Filed Aug. 24, 1964, Ser. No. 391,692 18 Claims. (Cl. 277-70)The present invention relates to well apparatus, and more particularlyto norm-ally retracted packing or sealing structures adapted to beexpanded into sealing relation with the wall of a surrounding well bore01 conduit string, such as well casing.

Heretofo-re, subsurface well apparatus, such as packers embodyingnormally retracted elastic packing elements or structures, have been runin well casing to a desired setting point, after which an endwisecompressive force has been impose-d on the packing device to shorten itand thereby expand it into sealing relation against the wall of the wellcasing.

During lowering of the apparatus through fluid in the well casing orwell bore, the fluid flowing relatively upwardly past the normallyretracted packing structure exerts suflicient force therein, as a resultof the pressure generated in the well bore fluid, to eflect inadvertentoutward expansion of the packing elements against the well casing. Suchexpansion may be due to the endwise force exerted by the fluid againstthe lower end of the packing element, tending to shorten it and expandit outwardly, or due to the fluid pressure passing to the interior ofthe packing element and ballooning it outwardly, or both.

The same inadvertent expansion has occurred in .the absence of loweringthe apparatus through fluid in the well casing or well bore, as forexample, upon pumping or circulating fluid down through the tubularstring to which the apparatus is secured, the fluid discharging from theapparatus and thenflowing upwardly around the exterior of the apparatusand its normally retracted packing structure.

Accordingly, an object of the present invention is to provide subsurfacewell apparatus embodying a normally retracted packing structure in whichthe fluid pressure developed at the packing structure, as a result oflowering the apparatus through fluid in the well bore, or otherwisecirculating fluid thereby, is incapable of expanding the packingstructure against the wall of the surrounding well casing or well bore.

Another object of the invention is to provide subsurface well apparatusembodying a normally retracted packing structure in which a fluidpressure differential is developed at the packing structure as a resultof lowering the apparatus through fluid in the well bore, or otherwisecirculating fluid thereby, which tends to retain the packing structurein its retracted position rather than expanding it outwardly.

A further object of the invention is to provide subsurface wellapparatus embodying a normally retracted packing structure of the typeexpandable outwardly by exerting an axial or endwise pack-off forcethereon, in which the fluid pressure developed at the packing structureas a result of lowering the apparatus through fluid in a well bore orotherwise circulating fluid thereby is incapable of expanding thepacking structure against the wall of the surrounding well casing orwell bore, the axial force to effect expansion of the packing structurebeing relatively :low when expansion is desired.

An additional object of the invention is to provide subsurface wellapparatus embodying a normally retracted packing structure in which afluid pressure differential is 3,334,907 Patented Aug. 8, 1967 icedeveloped at the packing structure as a result of lowering the apparatusthrough fluid in a well bore, or otherwise circulating fluid thereby,tending to retain the packing structure in its retracted position ratherthan expanding it outwardly, the pressure internally and externally ofthe packing structure being substantially equal when its outwardexpansion is desired, holding to a minimum the force required to effecta full and complete pack-off of the packing structure against the wallof the well bore or casing.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of severalforms in which it may be embodied. Such forms are shown in the drawingsaccompanying and forming part of the present specification. These formswill now be described in detail for the purpose of illustrating thegeneral principles of the invention; but it is to be understood thatsuch detailed description is not to be taken in a limiting sense, sincethe scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a combined longitudinal section and side elevational view ofan apparatus embodying the invention, with the packing structure in itsretracted position;

FIG. 2 is a longitudinal section through the apparatus disclosed in FIG.1, with the packing structure expanded against the wall of thesurrounding Well casing;

FIG. 3 is an enlarged fragmentary sectional view of. the packingstructure disclosed in FIG. 1;

FIG. 4 is a longitudinal section of a portion of a modified packingstructure;

FIG. 5 is a section taken along the line 55 on FIG. 4;

FIG. 6 is a sectional view of a portion of a packing element embodied inand forming part of the packing structure; FIG. 7 is a view of thepacking structure disclosed in FIG. 1, with the fluid pressures imposedon the packing structure as a result of fluid flowing thereby beingrepresented graphically.

As disclosed in the drawings, a packing structure A constitutes part ofa well packer B adapted to be lowered through fluid in a well casing Cby means of a tubular running-in string D extending to the top ofthewell bore. The packing structure can be used in a variety of Wellpackers. By way of example, a portion of a well packer is disclosed,which includes a tubular body 10, the upper end of which is threadedlyattached to a body coupling 11, which is, in turn, threadedly attachedto the lower end of a tubing section D thereabove. Surrounding the bodyis a sleeve or outer .body 12 threadedly secured to an upper head 13forming a portion of an upper abutment 114, an upper gage ring 15 beingthreaded on this head. A lower abutment 16 is slidably mounted on thesleeve or body 12 and may be constituted as a lower expander 17 with alower gage ring 18 threadedly mounted thereon. The expander 17 isadapted to move relatively downwardly within a plurality of taperedslips 19 carried by a slip ring 25 slidably mounted on the body 12 forthe purpose of expanding the slips outwardly into anchoring engagementwith the wall of the well casing C. The control mechanism for initiallyretaining the slips 19 in retracted position, or for that matterinitially preventing inadvertent upward movement of the expander 17along the sleeve 12, forms no part of the present invention, and forthat reason is not illustrated. Such control mechanisms are well known,and may include, for example, a simple J-slot and pin arrangement (notshown).

The packing structure A specifically illustrated includes upper,intermediate and lower pliant elastic packing elements 35, 36, 37 madeof rubber or rubber-like material,

although it is to be understood that the invention is applicable to apacking structure embodying a single packing element. The upper element35 has its upper end engaging the gage ring of the upper abutment andits lower end engaging a spacer ring 38, which, in turn, is engaged bythe upper end of the intermediate element 36. The lower end of theintermediate element engages a spacer ring 39, which, in turn, engagesthe upper end of the lower element 37. The lower end of such elementengages the lower abutment or gage ring 18.

Each packing element has its upper and lower ends 40, 41 tapered orbeveled, its outer surface 42 between such beveled portions beingcylindrical and having an initial diameter substantially less than theinternal diameter of the well casing C in which the apparatus is run,and against which the packing elements 35, 36, 37 are to be expanded.The packing elements inherently or normally tend to occupy a retractedposition, such as disclosed in FIGS. 1 and 3. They are expandedoutwardly by moving the upper abutment 14 towards the lower abutment 16.As illustrated, after the setting point in the well casing is reached,the tubing string D is appropriately manipulated to release the lock orcontrol mechanism (not shown) retaining the slips 19 in retractedposition, so that the tubing string and body can be moved downwardly, asuitable device, such as friction drag springs or blocks (not shown)engaging the wall of the casing C resisting the downward movement of theslips. As the body 10 moves downwardly, its coupling 11 engages theupper abutment head 13, the packing structure A and expander 17 thenbeing shifted downwardly as a unit, the expander moving within the slips19 and expanding them outwardly against the wall of the well casing.

Upon anchoring engagement of the slips 19 with the casing wall, theexpander 17 and the lower abutment 16 cannot move downwardly to anyfurther extent. Accordingly, the exertion of a downward force on thetubing string D and body 10 will shift the upper abutment 14 toward thelower abutment 16, shortening the lengths of the packing elements 35,36, 37 and expanding them outwardly into fi-rm sealing engagement withthe wall of the well casing C and also against the sleeve or body 12,the parts then being disposed in the position illustrated in FIG. 2, inwhich the well packer B is anchored in packed-off condition in the wellcasing against downward movement therewithin. As assurance that fluidleakage will not occur between the inner body 10 and the outer body 12,a suitable side seal ring 45 is mounted in the upper head 13 which sealsagainst the periphery of the body 10.

During lowering of the well packer apparatus B in the well casing C, thefluid therein flows relatively upwardly past the packing elements 35,36, 37, a pressure being developed in the fluid which tends to exert anupward force against the lower end of each packing element and shift itin an upward direction, to effect its shortening and outward expansion.Even a partial outward expansion restricts the annular path of the fluidflow relatively upwardly along each packing element, thereby increasingthe back pressure of the fluid which additionally forces the packingelements upwardly to shorten and eflect their outward expansion. Inaddition to the tendency of the fluid pressure developed in the fluid inthe well casing to shorten the packing elements, such fluid pressurealso passes to the interior of each packing element 35, 36, 37, creatinga greater pressure the-rewithin than occurs externally thereof. Suchgreater pressure tends to balloon or expand the packing elementsoutwardly against the casing wall. As a result of the foregoing, thefluid pressure effects an undesired outward expansion of each packingelement, and may cause them to slide along the casing wall, creating aswabbing action in the well casing, if not actually tearing or otherwisedisrupting the packing elements themselves.

The aforenoted action also tends to occur in the event fluid is pumpeddown the tubing string D and out through the lower end of the body 10,then passing upwardly through the annular spaces between the packingstructure A and the wall of the well casing C.

The aforenoted difliculties are overcome with a packing system, such asdisclosed in the drawings. The fluid pressure is prevented from exertinga 'suflicient upward force on the lower ends of each packing element asto effect their shortening, and it is also prevented from passing to theinterior of the packing elements and thereby expand them outwardly.Contrary to this arrangement, the fluid pressure is availed of toactually exert an inward force retaining each packing element 35, 36, 37in its retracted position. Despite the presence of such inward force,when the packing elements are to be shortened and expanded outwardlyagainst the wall of the well casing C, the fluid pressure is equalizedaround each packing element so that no increase in the compressive forceis required to effect full expansion of each packing element against thewall of the well casing, as well as against the body 12 that itsurrounds.

As disclosed in FIGS. 1, 2, 3, 6 and 7, each packing element has upperand lower end or lip seals 50, 51, the seals extending laterallyoutwardly and in a direction toward adjacent abutment 15, 18 and spacerrings 38, 39. In addition, a seal 52 is provided between the lowerportion of each packing element and the sleeve or body 12 on which it ismounted. Accordingly, as the packer B is lowered through fluid in thewell casing, or in the event of the circulation of fluid through thepacker and upwardly therearound, any fluid pressure developed will acton the lip seals 50, 51 and urge them into sealing engagement with theircompanion abutments 15, 18 or spacer rings 38, 39, thereby preventingthe relatively high fluid pressure externally of each packing elementfrom passing to its interior.

The seal between the lower portion of each packing element and the body12 is effected, as shown in the drawings, by providing an inner seal orrib 52 projecting inwardly from the main body of the packing element,which will be compressed against the periphery of the sleeve 12 when thepacking element is mounted thereon, since the normal unrestrainedinternal diameter of the rib 52 is less than the external diameter ofthe sleeve or body 12. Not only is fluid pressure externally of eachpacking element prevented from passing to its interior, but the packingelement system disclosed actually produces an external pressuredifferential tending to force or urge each packing element inwardlyagainst the sleeve or body 12, by causing the fluid flowing past thepacking structure A to decrease the pressure internally of each packingelement.

As shown in the drawings, the spacer ring 39 above the lower packingelement 37 has one or a plurality of fluid ports 60 extendingtherethrough establishing communication between the exterior of the ringand the interior of the lower packing element 37 above its seal rib 52.A similar fluid or vent port 60 is provided in the spacer ring 38 abovethe intermediate packing element 36 and in the abutment or gage ring 15above the uppermost packing element 35. Thus, the interior of eachpacking element above its sealing rib 52 communicates with the exteriorof the ring thereabove, so that the pressure of the fluid in theinterior of each packing element above its seal rib is substantially thesame as the pressure of the fluid in the annular space 61, 62 or 63between the periphery of the ring thereabove and the wall of thesurrounding well casing C. The lower or end lip seal 51 prevents thefluid pressure at and externally of the lower end of its packing elementfrom getting under it and tending to urge the packing element axiallyupwardly. If any fluid does get under the lower end of a packingelement, it cannot pass to its interior because of the seal provided bythe rib 52 at the lower end portion of the element and the periphery ofthe sleeve or body 12.

Assuming that the well packer B and its packing structure A are in theirinitial position, as disclosed in FIGS. 1 and 3, and that the apparatusis being lowered through the liquid or fluent material in the wellcasing C on the tubing string D, such fluid will flow relatively in anupward direction past the packing structure. The pressure externally ofthe apparatus that it develops in moving through the fluid is preventedfrom being exerted within the interior of each packing element by theend lip seal 51 and by the seal rib 52 sealing aaginst the periphery ofthe sleeve or body 12. Similarly, the fluid pressure surrounding theupper portion of each packing element cannot pas therearound to theinterior of the packing element because of the sealing effectiveness ofthe upper lip seal 50 against the lower end of the adjacent ring 39',38, 15. However, the fluid flowing through the annular space 61, 62 or63 between each ring 39, 38 or 15 and the wall of the surrounding wellcasing effects a decrease in the pressure of the fluid within the ports60 and, consequently, in the interior of the packing element above itsseal rib 52 that is communicating therewith.

The total fluid pressure passing the exterior of each ring isrepresented by the sum of its static pressure and its velocity pressure.Because of the flow velocity past the fluid ports, the static pressurewithin the ports 60 will be decreased much in the nature of theaspirating effect of fluid flowing past an orifice, thereby causing thestatic pressure of the fluid within each packing element 37, 36, 35 tobe less than the static pressure of the fluid externally and surroundingthe packing element. Accordingly, there is a pressure differentialcreated on the exterior of the packing element tending to urge it andhold it inwardly in its retracted position.

The static fluid pressure internally of each packing element can be madestill less than the static fluid pressure externally thereof byproviding each ring above a packing element with a greater externaldiameter than the external diameter of the cylindrical periphery 42 ofthe packing element therebelow. Accordingly, the fluid flowing upwardlypast a packing element at a certain velocity must accelerate in flowingthrough the lesser annular area 61, 62 or 63 between the ring above thepacking element and the surrounding well bore. Thus, the static pressureof the fluid moving past the fluid port 60 in a ring will besubstantially less than the static pressure of the fluid surrounding thepacking element itself. A greater pressure difierential is therebyprovided externally of the packing element with respect to the pressureinternally thereof than would be available in the event that thediameters of the packing elements 35, 36, 37 and rings 15, 38, 39 weremade equal, or substantially so.

The provision of a greater pressure diiferential externallly of eachpacking element occurs under other operating conditions in the wellbore. For example, if the setting location in the well casing has beenreached and fluid is circulated down through the tubing string D and thepacker body 10, which will then pass upwardly around the well packer Band through the annular spaces between the packing structure A and thewall of the well casing C, the same pressure differentials noted abovewill be developed, tending to force and hold each packing element in itsinward, retracted position, rather than tending to effect an expansionof each packing element, as by acting over its lower end area to shortenit and expand it outwardly, and by its ability to flow along the lowerend of the packing element into its interior, in order to swell andballoon the packing element outwardly, because of a greater pressurebeing developed interiorly of the packing element than exists externallythereof, much in the nature of a downwardly facing swab cup.

When the setting location is reached in the well bore, the well packercan be set in the manner described above merely by setting down on thetubing string D and body C to shorten the packing structure and expandits packing elements laterally outwardly. The endwise mechanical forcerequired to shorten each packing element and expand it outwardly is heldto a minimum, since the interior and exterior of each packing elementare in communication with each other. After relative fluid flow pasteach packing element has ceased, that is, with a quiescent fluid statein the well casing C with respect to each packing element, the port orports 60 eifect communication between its interior and exterior, so thatthe pressures internally and externally of each packing element areequal. Accordingly, there is no fluid pressure acting on any packingelement 35, 36 or 37 tending to resist its outward expansion as a resultof its being shortened. If, for example, the upper and lower ends of thepacking clement were sealed against the body 12, air at atmosphericpressure would be trapped within the element between its upper and lowerends, and the hydrostatic head of fluid in the Well casing would tend tohold each packing element laterally inwardly. The exertion of theendwise force on each packing element for the purpose of shortening itand expanding it outwardly would then have to overcome the inwardholding force of the external hydrostatic head. As a result, a muchgreater endwise or compressive force would be required to eifect outwardexpansion of each packing element into firm sealing engagement with thewall of the well casing than is required in the packing structureillustrated in the drawings, in which there is no hydrostatic pressuredifferential present when a pack-01f condition is to be achieved.

Actually, in expanding each packing element 35, 36, 37 in the systemillustrated in the drawings, the exertion of an endwise or axial forcethereon causes each packing element to first bulge outwardly to bringits mid-portion into contact with the casing C, after which the ends ofthe packing element are moved toward each other until a full and solidpacked-off condition, such as illustrated in FIG. 2, has been achieved.A lesser packed-off force is required because of the ability of thepacking element to bulge outwardly initially. Where the hydrostatic headdifi'erential is acting on the exterior of the packing element andtending to hold it inwardly, the outward bulging tendency is severelyresisted, if not prevented entirely, being a partial cause of thenecessity for imposing a much greater endwise force on the packingelement to eflect its full expansion into sealing engagement with thewall of the well casing and also against the periphery of the sleeve orbody 12 that it encompasses.

The pressure relationship externally of the packing structure and itsinterior is shown diagrammatically in FIG. 7, which represents actualpressure readings taken with a typical flow rate of fluid past thepacking elements, which, for example, could be approximate 400 gallonsper minute. Two curves are disclosed in FIG. 7, the solid linerepresenting the pressure externally of the packing elements 35, 36, 37and adjacent rings 15, 38, 39, 18, and the broken line representing thepressure under the packing elements.

Beginning with the lower end of FIG. 7, the fluid flowing past the lowerportion of the lower packing element 37 will have a relatively highstatic pressure due, in part, to the increased annular area asurrounding the lower beveled portion of the packing element and alsothe fluid turbulence created in such region. The pressure of the fluidflowing past the lower abutment or ring 18 is relatively low because ofthe relatively high velocity of the fluid passing'through the restrictedannular space between this ring and the well casing C. When the fluidreaches the lower beveled or tapered region a of the lower packingelement, the area is much greater so that the velocity pressuredecreases and the static pressure increases. Thus, at the region a, thepressure has a value designated a in the pressure diagram which has beenincreased somewhat because of the fluid turbulence in the region a. Asthe fluid flows upwardly through the region b between the periphery ofthe lower packing element 37 and the casing C, its velocity increasesrelative to the region a and the static pressure b decreases, thedecrease being progressive due to the friction pressure drop as thefluid flows along the packing element. When the region is reached at theupper beveled portion 40 of the lower packing element, the fluidvelocity again decreases because of the increased annular area, thestatic pressure increasing, as represented on the graph at 0, some ofthe increase in pressure being due to the turbulence of the fluid inthis area.

As the fluid flows through the region a between the periphery of thelower spacer ring 39 and the Well casing C, its velocity increasesbecause of the reduced annular area 61 through which the fluid mustflow, the static pressure dropping considerably in the region of theport 60, the great drop in pressure being represented on the curve bythe letter d. This is the same pressure that will be present interiorlyof the lower packing element 37 above its seal rib 52, since suchinterior of the packing element is in fluid communication with the port60. This pressure is also represented by the letter d in the broken linecurve. It is evident that the pressure differential tending to hold thepacking element 37 inwardly is the pressure at the region b surroundingthe packing element and .the internal pressure d. In the example shownin FIG. 7,

such differential is in excess of 100 p.s.i., as read on the abscissascale of the inches-pressure diagram.

As the fluid continues to flow upwardly, it will leave the restrictedannular area around the ring 39 at the region :1 and pass through theregion e where the intermediate packing element 36 is beveled. As inconnection with the lower element, the pressure surrounding the lowerportion of the rubber or rubber-like packing element 36 will increasesubstantially from the pressure d, being designated e on the curve. Asthe fluid flows upwardly past the cylindrical portion 42 of theintermediate packing element 36 through the region the pressureprogressively drops until the upper beveled region g is reached,whereupon it increases to a slight extent. The fluid then flows throughthe restricted annular area h surrounding the upper spacer ring 38,where the fluid accelerates considerably in velocity, the staticpressure decreasing to a substantial extent, as represented at h on thepressure curve. The same pressure h will be present interiorly of theintermediate packing element 36 because of the communication between theannular space 11 and the interior of the packing element through thevent or equalizer port 60 extending through the ring 38. Again, there isa substantial pressure differential between the pressure externally ofthe intermediate packing element 36 and the pressure h interiorly of thepacking element, which is of the order of about 50 p.s.i. as shown onthe diagram by way of example.

As the fluid continues to flow upwardly past the packing structure, itwill enter the region j of greater area adjacent to the lower beveledportion of the upper packing element 35, the pressure rising to thevalue 1', as shown on the pressure diagram, after which the fluid flowsupwardly through the region k surrounding the periphery 42 of thepacking element 35, whereupon the pressure k progressively drops untilthe upper region of turbulence in at the upper beveled portion 40 of theupper packing element is reached, where the pressure In will againincrease. From this region, the fluid will flow past the restrictedannular space p surrounding the upper gage ring 15, where its velocityis increased substantially, resulting in a reduced static pressure p atthe region of the port 60 which will result in the same pressure p beingpresent in the interior of the upper packing element 35 above its sealrib 52, as designated at p in the broken line curve, which indicates thepressure under the packing element. As in connection with the otherpacking elements, a pressure differential is present externally of thepacking element, tending to hold it inwardly, such differential beingshown in the graph as being about 35 p.s.i.

It is evident that the seal assembly disclosed results in the presenceof a greater pressure differential exter nally of each packing elementthan exists internally thereof during the time that fluid i flowingrelatively past the packing element, which will retain each packingelement in its retracted position. The fluid pressure externally of andat the lower end of each packing element cannot pass inwardly thereofbecause of the sealing action of the lip seal 51 against its companionring member or abutment. Moreover, the fluid pressure internally of alower packing element cannot pass to the interior of a packing elementthereabove because of the sealing action of the rib seal 52 against theperiphery of the sleeve or body 12. Thus, each packing element isactually a separate hydraulic unit, in which fluid flowing past itsexterior will exert a pressure differential tending to hold it inwardly.

Despite the fact that the fluid pressure developed in the well casing orwell bore tends to hold each packing element inwardly, upon cessation ofsuch fluid flow, which may result from the arresting of downwardmovement of the apparatus in the well casing, or as a result of thecessation of pumping of fluid down through the tubing string C and body10 of the well packer for upward movement past a stationary apparatus B,the internal and external pressures become equalized because of theintercommunicating ports or passages 60. Accordingly, there is no fluidpressure differential acting across the packing element which, forexample, might tend to hold it inwardly. Accordingly, such pressuredifferential need not be overcome in shortening each element 35, 36 or37 to expand it outwardly, the expanding force being held at a minimumfor effective sealing of each element against the wall of the wellcasing C and against the periphery of the sleeve or body 12.

In the form of invention illustrated in FIGS. 4 and 5, the upperabutment 14a may not have a port there through. As an example, a gagering 15a is merely threaded onto a threaded portion of the head 13.However, a low pressure interiorly of the uppermost packing element willstill be obtained by cutting transverse and radial slots 70 through theupper lip sealing portion 50a of the packing element 35a, establishingcommunication between its interior and exterior. The pressure at the lipseal 50a will still be less than the general pressure externally of thepacking element 35a therebelow, so that the pressure internally of thepacking element above its sealing rib 52 will be less than the externalpressure, the external pressure tending to hold the packing element inits retracted position. When fluid flow past the upper packing elementceases, the internal and external pressures will equalize because of theintercommunicating slot or port 70 through the upper lip member 50a,facilitating shortening of the packing element 35a and its outwardexpansion against the well casing C.

If desired, the intermediate packing element 36 may be made of a softerrubber or rubber-like material than the upper and lower packing elements35, 37. To assist in the retention of such packing element 36 in itsretracted position, the separator rings 38, 39 may have axial flangesfacing one another and encompassing at least partially the upper andlower beveled portions 40, 41 of the intermediate packing element.Despite the fact that the intermediate element is made of a softerpacking material, the pressure of the fluid flowing past it will stillbe incapable of shortening it and expanding it outwardly since theexternal pressure will be predominant. When the intermediate packingelement 36 is to be expanded, such expansion will occur with lower axialforces imposed thereon because of its lesser resistance to deformation.

I claim:

1. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said body;upper and lower abutments on said body engaging upper and lower portionsof said packing member, respectively, and movable toward each other toshorten and expand said packing member laterally outwardly; said upperand lower abutments being disconnected from said packing member; meansproviding a direct seal between said body and said packing member at oneend portion thereof; means providing a passage establishing fluidcommunication between the interior of said packing member and itsexterior at its other end portion; and means for causing fluid flowingpast the exterior of said packing member and said passage to produce alesser static pressure in said passage and interior of said packingmember than the static pressure externally of said packing member.

2. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said body;upper and lower abutments on said body engaging upper and lower portionsof said packing member, respectively, and movable toward each other toshorten and expand said packing member laterally outwardly; said upperand lower abutments being disconnected from said packing member; meansproviding a direct seal between said body and said packing member at itslower end portion; means providing a passage establishing fluidcommunication between the interior of said packing member and itsexterior at its upper end portion; and means for causing fluid flowingrelatively upwardly past the exterior of said packing member and saidpassage to produce a lesser static pressure in said passage and interiorof said packing member than the static pressure externally of saidpacking member.

3. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said body;upper and lower abutments on said body engaging upper and lower portionsof said packing member, respectively, and movable toward each other toshorten and expand said packing member laterally outwardly; said upperand lower abutments being disconnected from said packing member; meansproviding a direct seal between said body and said packing member at oneend portion thereof; said packing member having an end seal at said oneend portion sealing against an abutment at said one end portion; meansproviding a passage establishing fluid communication between theinterior of said packing member and its exterior at its other endportion; and means for causing fluid flowing past the exterior of saidpacking member and said passage to produce a lesser static pressure insaid passage and interior of said packing member than the staticpressure externally of said packing member.

4. In a well tool adapted to be disposed in a-well bore: a body; anormally retracted annular pliant elastic packing member on said body;upper and lower abutments on said body engaging upper and lower portionsof said packing member, respectively, and movable toward each other toshorten and expand said packing member laterally outwardly; said upperand lower abutments being disconnected from said packing member; meansproviding a direct seal between said body and said packing member at itslower end portion; said packing member having an end seal at its lowerend portion sealing against said lower abutment; means providing apassage establishing fluid communication between the interior of saidpacking member and its exterior at its upper end portion; and means forcausing fluid flowing relatively upwardly past the exterior of saidpacking member and said passage to produce a lesser static pressure insaid passage and interior of said packing member than the staticpressure externally of said packing member.

5. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said body;upper and lower abutments on said body engaging upper and lower portionsof said packing member, respectively, and movable toward each other toshorten and expand said packing member laterally outwardly; said upperand lower abutments being disconnected from said packing member; meansprovid ing a direct seal between said body and said packing member atone end portion thereof; said packing member having upper and lower endseals sealing against said upper and lower abutments, respectively; saidabutment at the other end portion of said packing member having apassage therethrough establishing fluid communication between itsexterior and the interior of said packing member; and means for causingfluid flowing past the exterior of said packing member and said passageto produce a lesser static pressure in said passage and interior of saidpacking member than the static pressure externally of said packingmember.

6. In a well tool adapted to be disposed in a well bore: a body; a,normally retracted annular pliant elastic packing member on said body;upper and lower abutments on said body engaging upper and lower portionsof said packing member, respectively, and movable toward each other toshorten and expand said packing member laterally outwardly; said upperand lower abutments being disconnected from said packing member; meansproviding a direct seal between said body and said packing member at itslower end portion; said packing member having upper and lower end sealssealing against said upper and lower abutments, respectively; said upperabutment having a passage therethrough establishing fluid communicationbetween its exterior and the interior of said packing member; and meansfor causing fluid flowing relatively upwardly past the exterior of saidpacking member and said passage to produce a lesser static pressure insaid passage and interior of said packing member than the staticpressure externally of said packing member.

7. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said body;upper and lower abutments on said body engaging upper and lower portionsof said packing member, respectively, and movable toward each other toshorten and expand said packing member laterally outwardly; said packingmember having an inner circumferential rib at one end portion thereofengaging and sealing against the periphery of said body; means providinga passage establishing fluid communication between the interior of saidpacking member and its exterior at its other end portion; and means forcausing fluid flowing past the exterior of said packing member and saidpassage to produce a lesser static pressure in said passage and interiorof said packing member than the static pressure externally of saidpacking member.

8. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said body;upper and lower abutments on said body engaging upper and lower portionsof said packing member, respectively, and movable toward each other toshorten and expand said packing member laterally outwardly; said packingmember having an inner circumferential rib at its lower portion engagingand sealing against the periphery of said body; means providing apassage establishing fluid communication between the interior of saidpacking member and its exterior at its upper end portion; and means forcausing fluid flowing relatively upwardly past the exterior of saidpacking member and said passage to produce a lesser static pressure insaid passage and interior of said packing member than the staticpressure externally of said packing member.

9. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said body;upper and lower abutments on said body engaging upper and lower portionsof said packing member, respectively, and movable toward each other toshorten and expand said packing member laterally outwardly; said packingmember having an inner circumferential rib at one end portion thereofengaging and sealing against the periphery of said body; said packingmember having an end seal at said one end portion sealing against anabutment at said one end portion; means providing a passage establishingfluid communication between the interior of said packing member and itsexterior at its other end portion; and means for causing fluid flowingpast the exterior of said packing member and said passage to produce alesser static pressure in said passage and interior of said packingmember than the static pressure externally of said packing member.

10. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said body;upper and lower abutments on said body engaging upper and lower portionsof said packing member, respectively, and movable toward each other toshorten and expand said packing member laterally outwardly; said packingmember having an inner circumferential rib at its lower portion engagingand sealing against the periphery of said body; said packing memberhaving an end seal at its lower end portion sealing against said lowerabutment; means providing a passage establishing fluid communicationbetween the interior of said packing member and its exterior at itsupper end portion; and means for causing fluid flowing relativelyupwardly past the exterior of said packing member and said passage toproduce a lesser static pressure in said passage and interior of saidpacking member than the static pressure externally of said packingmember.

11. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said body;upper and lower abutments on said body engaging upper and lower portionsof said packing member, respectively, and movable to-- ward each otherto shorten and expand said packing member laterally outwardly; saidupper and lower abutments being disconnected from said packing member;said packing member having an inner circumferential rib at one endportion thereof engaging and sealing against the periphery of said body;said packing member having upper and lower end seals sealing againstsaid upper and lower abutments, respectively; said abutment at the otherend portion of said packing member having a passage therethroughestablishing fluid communication between its exterior and the interiorof said packing member; and means for causing fluid flowing past theexterior of said packing member and said passage to produce a lesserstatic pressure in said passage and interior of said packing member thanthe static pressure externally of said packing member.

12. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said body;upper and lower abut ments on said body engaging upper and lowerportions of said packing member, respectively, and movable toward eachother to shorten and expand said packing member laterally outwardly;said upper and lower abutments being disconnected from said packingmember; said packing member having an inner circumferential rib at itslower portion engaging and sealing against the periphery of said body;said packing member having upper and lower end seals sealing againstsaid upper and lower abutments, respectively; said upper abutment havinga passage therethrough establishing fluid communication between itsexterior and the interior of said packing member; and means for causingfluid flowing relatively upwardly past the exterior of said packingmember and said passage to produce a lesser static pressure in saidpassage and interior of said packing member than the static pressureexternally of said packing member.

13. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said bodyhaving an external cylindrical surface; upper and lower abutments onsaid body engaging upper and lower portions of said packing member,respectively, and movable toward each other to shorten and expand saidpacking member laterally outwardly; said upper and lower abutments beingdisconnected from said packing member; means providing a seal betweensaid body and said packing member at one end portion thereof; saidpacking member having upper and lower end seals sealing against saidupper and lower abutments, respectively; said abutment at the other endportion of said packing member having a passage therethroughestablishing fluid communication between its exterior and the interiorof said packing member; the diameter of said abutment at said other endportion of said packing member being substantially greater than thediameter of the external cylindrical surface of said packing member,whereby fluid flowing past the exterior of said packing member, abutmentat said other end portion and passage produces a lesser static pressurein said passage and interior of said packing member than the staticpressure externally of said packing member.

14. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said bodyhaving an external cylindrical surface; upper and lower abutments onsaid body engaging upper and lower portions of said packing member,respectively, and movable toward each other to shorten and expand saidpacking member laterally outwardly; said upper and lower abutments beingdisconnected from said packing member; means providing a seal betweensaid body and said packing member at its lower end portion; said packingmember having upper and lower end seals sealing against said upper andlower abutments, respectively; said upper abutment having a passagetherethrough establishing fluid communication between its exterior andthe interior of said packing member; the diameter of said upper abutmentbeing substantially greater than the diameter of the externalcylindrical surface of said packing member, whereby fluid flowing pastthe exterior of said packing member, upper abutment and passage producesa lesser static pressure in said passage and interior of said packingmember than the static pressure externally of said packing member.

15. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said bodyhaving an external cylindrical surface; upper and lower abutments onsaid body engaging upper and lower portions of said packing member,respectively, and movable toward each other to shorten and expand saidpacking member laterally outwardly; said upper and lower abutments beingdisconnected from said packing member; said packing member having aninner circumferential rib at one end portion thereof engaging andsealing against the periphery of said body; said packing member havingupper and lower end seals sealing against said upper and lowerabutments, respectively; said abutment at the other end portion of saidpacking member having a passage therethrough establishing fluidcommunication between its exterior and the interior of said packingmember; the diameter of said abutment at said other end portion of saidpacking member being substantially greater than the diameter of theexternal cylindrical surface of said packing member, whereby fluidflowing past the exterior of said packing member, abutment at said otherend portion and passage produces a lesser static pressure in saidpassage and interior of said packing member than the static pressureexternally of said packing member.

16. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said bodyhaving an external cylindrical surface; upper and lower abutments onsaid body engaging upper and lower portions of said packing memher,respectively, and movable toward each other to shorten and expand saidpacking member laterally outwardly; said upper and lower abutments beingdisconnected from said packing member; said packing member having aninner circumferential rib at its lower portion engaging and sealingagainst the periphery of said body; said packing member having upper andlower end seals sealing against said upper and lower abutments,respectively; said upper abutment having a passage therethroughestablishing fluid communication between its exterior and the interiorof said packing member; the diameter of said upper abutment beingsubstantially greater than the diameter of the external cylindricalsurface of said packing member, whereby fluid flowing past the exteriorof said packing member, upper abutment and passage produces a lesserstatic pressure in said passage and interior of said packing member thanthe static pressure externally of said packing member.

17. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said body;upper and lower abutments on said body engaging upper and lower portionsof said packing member, respectively, and movable toward each other toshorten and expand said packing member laterally outwardly; said upperand lower abutments being disconnected from said packing member; meansproviding a direct seal between said body and said packing member at itslower end portion; said packing member having upper and lower end lipseals sealing against said upper and lower abutments, respectively, toprevent inward passage of fluid from the exterior of said packing memberto its interior; said upper abutment having a passage therethroughestablishing fluid communication between its exterior and :the interiorof said packing member; and means for causing fluid flowing past theexterior of said packing member, upper abutment and passage to produce alesser static pressure in said 14 passage and interior of said packingmember than the static pressure externally of said packing member.

18. In a well tool adapted to be disposed in a well bore: a body; anormally retracted annular pliant elastic packing member on said bodyhaving an external cylindrical surface; upper and lower abutments onsaid body engaging upper and lower portions of said packing member,respectively, and movable toward each other to shorten and expand saidpacking member laterally outwardly; said upper and lower abutments beingdisconnected from said packing member; said packing member having aninner circumferential rib at its lower portion engaging and sealingagainst the periphery of said body; said packing member having upper andlower end lip seals sealing against said upper and lower abutments,respectively, to prevent inward passage of fluid from the exterior ofsaid packing member to its interior; said upper abutment having apassage therethrough establishing fluid communication between itsexterior and the interior of said packing member; the diameter of saidupper abutment being substantially greater than the diameter of theexternal cylindrical surface of said packing member, whereby fluidflowing past the exterior of said packing member, upper abutment andpassage produces a lesser static pressure in said passage and interiorof said packing member than the static pressure externally of saidpacking member.

References Cited UNITED STATES PATENTS 2,193,587 3/1940 Fortune et al27734 3,120,272 2/1964 Cochran 277102 X 3,215,208 11/1965 Tamplen 277102X 3,227,462 1/1966 Tamplen 277102 X SAMUEL ROTHBERG, Primary Examiner.

1. IN A WELL TOOL ADAPTED TO BE DISPOSED IN A WELL BORE; A BODY; ANORMALLY RETRACTED ANNULAR PLIANT ELASTIC PACKING MEMBER ON SAID BODY;UPPER AND LOWER ABUTMENTS ON SAID BODY ENGAGING UPER AND LOWER PORTIONSOF SAID PACKING MEMBER, RESPECTIVELY, AND MOVABLE TOWARD EACH OTHER TOSHORTEN AND EXPAND SAID PACKING MEMBER LATERNALLY OUTWARDLY; SAID UPPERAND LOWER ABUTMENTS BEING DISCONNECTED FROM SAID PACKING MEMBER; MEANSPROVIDING A DIRECT SEAL BETWEEN SAID BODY AND SAID PACKING MEMBER AT ONEEND PORTION THEREOF; MEANS PROVIDING A PASSAGE ESTABLISHING FLUIDCOMMUNICATION BETWEEN THE INTERIOR OF SAID PACKING MEMBER AND ITSEXTERIRO AT ITS OTHER END PORTION; AND MEANS FOR CAUSING FLUID FLOWINGPAST THE EXTERIOR OF SAID PACKING MEMBER AND SAID PASSAGE TO PRODUCE ALESSER STATIC PRESURE IN SAID PASSAGE AND INTERIOR OF SAID PACKINGMEMBER THAN THE STATIC PRESSURE EXTERNALLY OF SAID PACKING MEMBER.